scholarly journals Parton physics from a heavy-quark operator product expansion: Formalism and Wilson coefficients

2021 ◽  
Vol 104 (7) ◽  
Author(s):  
William Detmold ◽  
Anthony V. Grebe ◽  
Issaku Kanamori ◽  
C.-J. David Lin ◽  
Robert J. Perry ◽  
...  
Keyword(s):  
Heavy Quark ◽  
Operator Product Expansion ◽  
Operator Product ◽  
Quark Operator

Effective Field Theories for Heavy Quarks: Heavy Quark Effective Theory and Heavy Quark Expansion

2020 ◽  
pp. 560-615
Author(s):  
Thomas Mannel
Keyword(s):  
Heavy Quark ◽  
Particle Physics ◽  
Operator Product Expansion ◽  
Effective Field ◽  
Field Theories ◽  
Effective Theory ◽  
Tree Level ◽  
Operator Product ◽  
Heavy Quark Effective Theory ◽  
Inclusive Decays

The heavy quark effective theory (HQET) and the heavy quark expansion (HQE) have developed into the standard tools in heavy-flavour physics. The lectures in this chapter introduce the basics of the approach and illustrates the methods by discussing some of their phenomenological applications. The chapter covers construction of the HQET Lagrangian, symmetries of HQET, HQET at one loop, and HQET applications to phenomenology. It also discusses HQE inclusive decays, operator product expansion (OPE), tree-level results, HQE parameters, QCD corrections, and end-point regions. It concludes by reiterating the enormous impact that both HQET and the HQE have had on particle physics phenomenology.

scholarly journals HOW PENGUINS STARTED TO FLY

1999 ◽  
Vol 14 (30) ◽  
pp. 4705-4719 ◽  
Author(s):  
ARKADY VAINSHTEIN
Keyword(s):  
Cp Violation ◽  
Heavy Quark ◽  
Operator Product Expansion ◽  
Subsequent Development ◽  
Recent Measurement ◽  
Operator Product ◽  
Quark Masses ◽  
Weak Decays ◽  
Particle Phenomenology ◽  
History Of

A mechanism explaining a strong enhancement of nonleptonic weak decays was suggested in 1975, later to be dubbed the penguin. This mechanism extends Wilson's ideas about the operator product expansion at short distances and reveals an intricate interplay of subtle features of the theory such as heavy quark masses in Glashow–Iliopoulos–Maini cancellation, light quarks shaping the chiral properties of QCD, etc. The penguins have subsequently evolved to play a role in a variety of fields in present-day particle phenomenology. I will describe the history of this idea and review its subsequent development. The recent measurement of direct CP violation in K decays gives a new confirmation of the penguin mechanism.

scholarly journals High-energy operator product expansion at sub-eikonal level

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Giovanni Antonio Chirilli
Keyword(s):  
Operator Product Expansion ◽  
Evolution Equations ◽  
Energy Operator ◽  
High Energy ◽  
Structure Functions ◽  
Distribution Functions ◽  
Impact Factors ◽  
Operator Product ◽  
The Impact ◽  
New Distribution

Abstract The high energy Operator Product Expansion for the product of two electromagnetic currents is extended to the sub-eikonal level in a rigorous way. I calculate the impact factors for polarized and unpolarized structure functions, define new distribution functions, and derive the evolution equations for unpolarized and polarized structure functions in the flavor singlet and non-singlet case.

scholarly journals Conformal Regge theory at finite boost

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Simon Caron-Huot ◽  
Joshua Sandor
Keyword(s):  
Field Theory ◽  
Operator Product Expansion ◽  
Operator Product ◽  
Exact Results ◽  
Double Integral ◽  
Regge Theory ◽  
Conformal Field ◽  
Regge Trajectories ◽  
Continuous Spins ◽  
Regge Limit

Abstract The Operator Product Expansion is a useful tool to represent correlation functions. In this note we extend Conformal Regge theory to provide an exact OPE representation of Lorenzian four-point correlators in conformal field theory, valid even away from Regge limit. The representation extends convergence of the OPE by rewriting it as a double integral over continuous spins and dimensions, and features a novel “Regge block”. We test the formula in the conformal fishnet theory, where exact results involving nontrivial Regge trajectories are available.

Operator product expansion in the minimal subtraction scheme

1982 ◽  
Vol 119 (4-6) ◽  
pp. 407-411 ◽  
Author(s):  
K.G. Chetyrkin ◽  
S.G. Gorishny ◽  
F.V. Tkachov
Keyword(s):  
Operator Product Expansion ◽  
Operator Product ◽  
Minimal Subtraction ◽  
Subtraction Scheme ◽  
Minimal Subtraction Scheme

scholarly journals OPERATOR-PRODUCT EXPANSION AND ANALYTICITY

1999 ◽  
Vol 14 (30) ◽  
pp. 4819-4840
Author(s):  
JAN FISCHER ◽  
IVO VRKOČ
Keyword(s):  
Operator Product Expansion ◽  
Deflection Angle ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Operator Product ◽  
Coupling Constant ◽  
Expectation Value ◽  
Euclidean Region ◽  
The Deflection Angle ◽  
Class Of Functions

We discuss the current use of the operator-product expansion in QCD calculations. Treating the OPE as an expansion in inverse powers of an energy-squared variable (with possible exponential terms added), approximating the vacuum expectation value of the operator product by several terms and assuming a bound on the remainder along the Euclidean region, we observe how the bound varies with increasing deflection from the Euclidean ray down to the cut (Minkowski region). We argue that the assumption that the remainder is constant for all angles in the cut complex plane down to the Minkowski region is not justified. Making specific assumptions on the properties of the expanded function, we obtain bounds on the remainder in explicit form and show that they are very sensitive both to the deflection angle and to the class of functions considered. The results obtained are discussed in connection with calculations of the coupling constant αs from the τ decay.

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